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E39 (1997 - 2003) The BMW 5-Series (E39 chassis) was introduced in the United States as a 1997 model year car and lasted until the 2004 when the E60 chassis was released. The United States saw several variations including the 525i, 528i, 530i and 540i. -- View the E39 Wiki

Since I bought the car these functions didn't work so that means no cruise control no audio functions and I just want to get them to work the only lights I have on my dash is the DSC light which I need to fix too and the air bag light

The clock spring is what connects the airbag, horn, and the steering wheel to the car. Take out your airbag ( 2 T30 bolts on either side of the back of the steering wheel), then take off the 16mm bolt that holds the steering wheel on. Unplug the two connectors that are right above the 16 mm bolt, and pull on the wheel. On the backside of the wheel, you will see the clock spring. It is a circular black plastic assembly with a tab that sticks out. A bad clock spring will cause your airbag light to come on.

Have NOT done my E39 clockspring yet, but replaced the clockspring on my 1998 Volvo V70.

In most cars this is what it looks like.
Once you understand one clockspring, you understand the rest.
I wrote it up in Volvo forum. The principle of repair is the same: d/c battery, use precaution etc.
Otherwise it is a straightforward procedure.

I see the air bag light is illuminated...and that means there's either something wrong with the SRS (supplemental restraint system) or it's the first signs that the ignition switch is failing...especially when a lot of seemingly unrelated electronic gremlins occur (which it appears they are in this situation).

Start your car, turn on the headlights and radio etc...then reach up and pull down the passenger sun visor then open the cover to the mirror. If you do this and more weird things happen (like the steering wheel moves, interior lights come on, radio turns on/off, horn start or stops working, cruise control won't engage, etc)...then more than likely the ignition switch is your culprit.

I know that the sun visor test sounds odd...so I made a short video to show how unbelievable the connections are of the components that are affected by the ignition switch.

You can see the steering wheel move up/down when I open the mirror cover on the sun visor, and the interior lights fade on/off...and the radio shut off:

I'd agree that you should check ignition switch.
Common things are common.
The E39 ignition switch is a commonly failed item.
Do the ignition switch first, then if the problems persist, check the clockspring.

...What is this clock spring your talking about is it hard to replace?

Another word for the "clock spring" is "slip ring"...which is what BMW calls it.

The slip ring (aka clock spring) is item #2 in the diagram below:

You can also see the slip ring (clock spring) in this pic below...it is the round thingy with wires sticking out of it on the back of a 3 spoke M steering wheel...it allows wires to run into the steering wheel to power the MFL buttons etc...while allowing full rotational function of the wheel without wires getting all twisted up:

The slip ring is usually easy to replace if you keep the ribbon in place...if you try to unroll the ribbon...then it can get frustrating trying to roll it back up.

Get a clock spring off of a 2002-2003 5 series. It is a possibility for the ignition switch to go bad, but it is most likely the clock spring. If anything, get the airbag light scanned, and if it says drivers front airbag communication, you definitely have a bad clock spring. I work on E39s and E46s every day for a living.